Melt butter over medium heat, add flour whisk for 2-3 min.
Gradually stir in milk. Cook 3 to 5 min. or until thickened, stir frequently.
Add mozzarella cheese.
Add Velveeta; cook 3 min. or until melted, stirring frequently.
Layer in greased casserole pan (or oven-safe individual bowls) half of macaroni noodles, cheese sauce, cheddar & Colby cheeses.
Bake 350° for 30-35 minutes until golden brown.